What Skill or technique was to hardest for you to learn/master?

We all have such different styles , but wonder if there is a common group of skills/techniques that seem to be the tough ones to conquer ? What was it for you that was difficult when starting out quilting or still is that "mountain" that just can not seem to be climbed?

Free Motion Quilting is the thing that has been hardest for me. I'm not good at it; but I'm getting better. I just need to practice more. Let's face it, piecing a quilt top is much more fun for me than FMQ. I think once I learn to FMQ better, the process will be relaxing.

I actually have 2. FMQ has to be #1 on my list. I just dont know if I have the patient to keep trying. I like the look of handquilting so much better. Other than that.. sometimes keeping a 1/4 inch seam over large seams sometimes are a struggle. (Hopefully that is the machine and not me)